The present invention relates to a cable termination socket for large diameter cables that has a two piece socket housing, which, when assembled, will receive a wedge as a locking device. The housing can be disassembled into its two pieces to permit removal of the wedge.
Large diameter wire ropes or cables used in the mining industry, for example, utilize cable termination sockets that have wedges to lock the cable in place at the present time. Termination sockets are used to connect the end of cables to equipment, such as dragline buckets. A typical prior art cable termination socket is shown in U.S. Pat. No. 3,905,711. That termination socket has a specific type of wedge that wedges the wire rope in place in a housing. Other devices merely use a one-piece socket housing and a wedge of fixed shape that wedges the cable against interior surfaces of the housing. Another type of termination socket is shown in U.S. Pat. No. 1,622,110, which has a simple wedge center portion that wedges a cable within an outer housing. An auxiliary wedge is also used for holding the cable in place.
One standard method of removing cable ends and wedges from one-piece cable end sockets at most U.S. surface mines today uses the explosive impact of a projectile fired from a cannon blasting the wedge from the cable socket housing. Another method is to cut the cable live end off at the socket and disconnect the cable socket from the bucket or tool. The cable socket assembly is then transported to the mine shop where it is placed in a special holding jig and the wedge is pressed out with a large hydraulic press or hydraulic jack.
The cable needs to be cut at three locations before the wedge can be extracted from the one-piece cable socket when using either the cannon or hydraulic press method. When using the cannon method, there is a need for some type of heavy equipment to back up the cannon when it discharges the projectile against the wedge.
There is also a need of a primer cord, detonator and a certified shooter to blast the wedge from the one-piece cable socket when a cannon is used. The methods used today by surface mining companies for removing cable retaining wedges from one-piece cable sockets is dangerous because of the resultant force required to remove the wedge from the one-piece cable socket. If there is danger to personnel, equipment, parts and machinery.
There are a large number of excavating machines (draglines and shovels) using cables of sizes of 2 inches in diameter up to 5-51/2 inches in diameter that now require the cannon or hydraulic press method to remove the wedge from the one-piece cable socket housing, due to the high tension loads applied to the cables, which causes the wedges to seat almost permanently. The larger excavating machines have a down time cost of $5,000.00 or more per hour in lost production, plus the labor and equipment charge cost. Changing out a set of cables on small dragline excavators may take two hours plus, and on the larger draglines excavators changing the cable termination sockets may take over eight hours when the one-piece cable socket housings and wedges are used.
Attempts have been made to solve this problem, including clamps such as those shown in U.S. Pat. Nos. 4,561,154 and 4,602,891. These patents disclose termination sockets that are made in two parts. In U.S. Pat. No. 4,602,891 the socket housing has a U-shaped housing over which a cap fits. The cap has tracks that slide on flanges to tighten down onto a cable and wedge in the housing. Other sockets which use special wedges or housings include U.S. Pat. No. 4,536,921. The varied conditions that are encountered during the removal of the cable from a cable termination socket continues to be a problem.
Typical rope type cable termination sockets are shown in U.S. Pat. Nos. 1,379,311 and 2,085,333. In addition, U.S. Pat. No. 4,718,788 shows a cable termination socket that has an equalizer arrangement.
A rope holder that has an expanding wedge is also shown in U.S. Pat. No. 4,218,328, and an explosively operated wedge for obtaining the wedging force is shown in U.S. Pat. No. 3,257,499.
The present invention of a two piece cable termination socket housing permits cable and wedge removal in a simplified manner after the cable has been cut once. The housing parts will separate from an impact that can be delivered by a pendulum ram, which is relatively easy to operate. The wedge thus can be released from the base portion of the socket housing.